The present disclosure relates to a power transmission device, a power transmission method, and a power transmission system.
Recently, power transmission systems capable of wirelessly transmitting power between devices have come into use. Examples of the above-described power transmission systems may be an electronic money system, a ticket gate system of a transportation facility, a system for entrance/admission using an employee identification (ID) card or the like, and an integrated chip (IC) card system using a reader/writer (an example of a power transmission device) and an IC card (an example of a power reception device). As a technology for wirelessly transmitting a larger amount of power to a greater distance, a technology for transmitting power, for example, by use of electric- or magnetic-field resonance, has also been developed.
Under these circumstances, a technology for wirelessly transmitting power to a specific device has been developed. An example of a technology for wirelessly transmitting power to a specific device by controlling directivity may be found in Japanese Patent Application Laid-Open No. 2009-253762.